Mechanical pump for removal of fragmented matter and methods of manufacture and use

ABSTRACT

Material transport catheters and methods for their use rely on rotation of an impeller within a catheter body and a clearing element for preventing buildup of materials at the opening of the catheter body. The impeller preferably comprises an inner tube or shaft having a helical rotor formed over an outer surface thereof. The clearing element may comprise a free end of a structure near the distal end of the catheter body for disrupting clot, wherein the free end of the structure extends into the distal opening of the catheter body to break up materials as the impeller is rotated. Alternatively, the clearing element may comprise a cutting member disposed at the distal opening of the catheter body.

CROSS-REFERENCES TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. application Ser. No.09/590,915, filed Jun. 9, 2000 (now U.S. Pat. No. 6,702,830), whichclaims benefit under 35 USC 119(e) of U.S. Provisional Application No.60/154,752, filed on Sep. 17, 1999, under 37 CFR §1.78(a)(3). Thisapplication is also a continuation-in-part of U.S. patent applicationSer. No. 10/680,367, filed on Oct. 6, 2003, which is a continuation ofU.S. patent application Ser. No. 10/162,276, filed on Jun. 3, 2002 (nowU.S. Pat. No. 6,660,014), which is a continuation-in-part of U.S.application Ser. No. 09/454,517, filed Dec. 6, 1999 (now U.S. Pat. No.6,454,775), the full disclosures of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to medical apparatus and methodsand more particularly to devices and methods for removal of unwantedtissue such as thrombus, atheroma, fluid, polyps, cysts or otherobstructive matter from body lumens, such as blood vessels, ureters,bile ducts or fallopian tubes.

Currently, there are many clinical approaches to removing unwantedmaterial, many of which are performed surgically, wherein the treatmentsite is accessed directly through a surgical incision.

In recent years, a variety of catheter devices have been developed foruse in intraluminal and intravascular procedures for fragmentation andremoval of obstructive matter, such as blood clots, thrombus, atheroma,and the like, from blood vessels. More recently, devices that can beinserted percutaneously through a puncture in the skin have beendeveloped to make the procedures less invasive. For example, a catheterdevice is inserted into a blood vessel at an access site located somedistance away from the intended treatment site, and is then advancedthrough the vessel lumen until the treatment site is reached. In mostinstances this approach is performed “over-the-wire,” a technique thatrequires the physician to first place a guidewire device into the vessellumen over which a larger catheter device can be tracked.

These techniques may employ various devices to fragment the unwantedclot or tissue from blood vessels such as rotating baskets or impellersas described in U.S. Pat. Nos. 5,766,191 and 5,569,275, cutters asdescribed in U.S. Pat. No. 5,501,694, and high pressure fluid infusionto create a Venturi effect as described in U.S. Pat. No. 5,795,322.Other devices rely on the principles of the Archimedes-type screw, suchas a one-piece solid machined screw to break up and/or remove clot.

In many instances, the luminal treatment techniques include infusing thevessel or treatment site with fluid (saline or a thrombolytic agent) toassist in breaking up the clot or tissue into a particle size that canthen be aspirated through a lumen of the treatment device or using asecondary catheter hooked up to a source of vacuum/suction. Depending onthe method of fragmentation and the consistency of the clot or tissue,the particle size can vary. If the material is not thoroughlyfragmented, the larger particles can build up in the catheter and blockthe aspiration lumen.

While these catheters and techniques have been fairly successful, thereis a need for improved devices for more efficiently evacuatingfragmented material from the vessel or body lumen in order to overcomethe difficulties of continued fluid infusion and material build up thatblocks the aspiration lumen. Furthermore, it would be desirable to havedevices that allowed aspiration of larger particles of fragmentedmaterial, thereby reducing procedure time. Preferably, such improveddevices will have a low profile to enable percutaneous use, and will beflexible and torqueable to enable their use in tortuous lumens.Furthermore, such devices will preferably be designed to be placed overa guidewire and will be structured to mechanically translate andtransport the fragmented material by directly pumping it through thecatheter shaft. Optionally, the devices should include mechanisms forinfusing materials, such as thrombolytic and other therapeutic agents,as well as disrupting the occlusive materials.

At least some of these objectives will be met by the design and use ofthe present invention.

2. Description of the Background Art

U.S. Pat. No. 5,556,408 describes an atherectomy cutter employing avacuum source for removal of loose stenotic material and other debrisfrom a vessel. Removal of thrombus by a rotating core wire on a driveshaft is described in U.S. Pat. No. 5,695,507 and fragmentation andremoval of tissue using high pressure liquid is described in U.S. Pat.No. 5,795,322. U.S. Pat. No. 4,923,462 describes a coiled wire coatedwith Teflon and used as a drive shaft to rotate a catheter. Furthermore,U.S. Pat. No. 5,334,211 describes a coiled guidewire used to stabilizean atherectomy device. Patents describing atherectomy catheters withrotating helical pumping elements in U.S. Pat. Nos. 4,732,154;4,886,490; 4,883,458; 4,979,939; 5,041,082; 5,135,531; 5,334,211;5,443,443; and 5,653,696. A rotary thrombectomy catheter having an innerhelical blade is commercially available under the tradename StraubRotarex® from Straub Medical AG, as described in a brochure with acopyright of August 1999. Use and construction of the Straub Rotarex®also appears to be described in Schmitt et al. (1999) Cardiovasc.Intervent. Radiol. 22: 504-509 and in U.S. Pat. Nos. 5,876,414 and5,873,882. Other patents of interest include U.S. Pat. Nos. 4,737,153;4,966,604; 5,047,040; 5,180,376; 5,226,909; 5,462,529; 5,501,694;5,569,275; 5,630,806; 5,766,191, 5,843,031; 5,911,734; 5,947,940; and5,972,019; as well as published PCT applications WO 99/56801; WO99/56638; and WO 98/38929. Motor drive units for catheters and otherdevices are described in U.S. Pat. Nos. 4,771,774 and 5,485,042.

SUMMARY OF THE INVENTION

According to the present invention, improved apparatus and methods areprovided for transporting material between a target site in a body lumenof a patient and a location external to the patient. In some cases, thematerials will be transported from the target site to the externallocation, which methods will generally be referred to as aspiration. Inother cases, the material may be transported from the external locationto the target site within the body lumen, which methods will generallyreferred to as infusion. In still other cases, materials may besimultaneously transported from the external location to the internaltarget site and transported away from the internal target site to theexternal location, referred to as circulation. In all cases, thematerial transport will be enhanced by rotation of an impeller disposedin a lumen of a catheter. The impeller will usually comprise a tubularor solid shaft having a helical rotor extending at least partially overan exterior surface thereof. Thus, rotation of the impeller will pumpthe material in the manner of an “Archimedes screw.”

In addition to such mechanical pumping, the methods and apparatus of thepresent invention may rely on supplemental pressurization of thecatheter lumen being used to transport the material. In particular, forinfusion, the liquid or other material to be introduced may be suppliedunder pressure, typically in the range from 0.1 psi to 10,000 psi,usually in the range from 5 psi to 350 psi. Conversely, in the case ofaspiration, a vacuum may be applied to the catheter lumen, usually from1 mmHg to 760 mmHg, usually from 5 mmHg to 760 mmHg.

The methods and apparatus of the present invention will be particularlysuitable for use in medical procedures for removing occlusive and othersubstances from body lumens, such as blood clots, thrombus, and thelike, from blood vessels. Catheters according to the present inventionwill be suitable for percutaneous introduction or introduction by asurgical cutdown to the blood vessel or other body lumen. Usually, thecatheters will then be advanced to a remote target site where thetreatment is performed. Preferably, the catheters of the presentinvention will be introduced over a guidewire in a so-called“over-the-wire” technique, although use of a guidewire will not alwaysbe required. Optionally, the apparatus of the present invention may beused in conjunction with a variety of other interventional catheters,particularly for intravascular treatments. For example, the materialtransport catheters of the present invention may be used to infusethrombolytic and other therapeutic agents and/or aspirate fragmentedclot, thrombus, and other occlusive materials in conjunction withangioplasty, atherectomy, laser ablation, embolectomy, endarterectomyand other known intravascular interventions. In particular, the materialtransport catheters of the present invention may be used in theprocedures described in copending U.S. patent application Ser. No.09/454,517, which has previously been incorporated herein by reference.

In a first aspect of the present invention, an over-the-wire materialtransport catheter comprises a catheter body having a proximal end, adistal end, and a lumen therebetween. An impeller is rotatably disposedin the lumen of the catheter body, and the impeller includes a tubularshaft having a central guidewire lumen therethrough. A helical rotorextends at least partially over an exterior surface of the tubularshaft, and it is intended that the material transport catheter beintroduced over a guidewire in a conventional manner. Moreover, theimpeller will usually be rotated over the guidewire, i.e., while theguidewire remains in place in the central guidewire lumen of theimpeller, during use of the catheter for aspiration and/or infusion.Optionally, the material transport catheter may further comprise amaterial capture device, such as a funnel structure, a macerator, or thelike, at or near the distal end of the catheter body. Alternatively, thedistal end of the catheter body may be substantially free fromsurrounding structure so that a desired material may be infused and/oraspirated directly through one or more ports in the catheter body at ornear its distal end.

In a second aspect, a selective infusion-aspiration catheter constructedin accordance with the principles of the present invention comprises acatheter body having a proximal end, a distal end, and a lumentherebetween. An impeller is rotatably disposed in the lumen of thecatheter body, and a driver is provided which is coupleable to theimpeller. By “coupleable,” it is meant either that the driver andimpeller are permanently connected, or more usually, that the driver isa separate component but that the driver and impeller are adapted toselectively mate and permit the driver to rotate the impeller while theimpeller remains disposed in the catheter body lumen. The driver will beadapted to selectively rotate the impeller in either a first directionto induce aspiration to the catheter body lumen or in a second directionto induce infusion through the catheter body lumen. In this way, theselective infusion-aspiration catheter can be used either for infusionor aspiration depending on the particular circumstances encountered. Theselective infusion-aspiration catheter may further comprise a materialcapture device disposed at or near the distal end of the catheter body,such as a funnel structure, a macerator, or the like. Alternatively, thedistal end of the catheter body may be substantially free fromsurrounding structure so that material may be aspirated and/or infusedthrough one or more ports located at or near the distal end of thecatheter body.

In a third aspect of the present invention, a circulation cathetercomprises a catheter body having a proximal end, a distal end, and atleast one lumen extending between the proximal end and the distal end. Afirst impeller is arranged in a lumen of a catheter body to aspiratematerials from the distal end to the proximal end of the catheter bodywhen the impeller is rotated. A second impeller is arranged in a lumenof the catheter body to infuse materials from the proximal end of thecatheter body to the distal end of the catheter body when the secondimpeller is rotated. Since the circulation catheter includes twoseparate impellers, it is possible to rotate the impellerssimultaneously so that material can be infused to a target locationwithin a body lumen and simultaneously aspirated from that targetlocation. For example, the circulation catheter may be used to introducethrombolytic or other therapeutic agent to a blood vessel and tosimultaneously or sequentially remove the lysed clot, thrombus, andother materials from the blood vessel. Suitable thrombolytic and otheragents include GPIIIb/IIa antagonists, tissue plasminogen activator(tPA), calcium dissolving agents, urokinase (proUK), heparinized saline,and the like. Other therapeutic agents include fibrinolytics,anti-coagulants, antiplatlet drugs, anti-thrombin, gene therapy agents,chemotherapeutic agents, brachytherapy agents, and the like. Optionally,the first impeller and second impeller may terminate at spaced-apartports along the length of the catheter body so that the thrombolytic orother agent will be assured of having a minimum residence time withinthe blood vessel prior to being aspirated. Further optionally, the firstimpeller and second impeller may be disposed in separate lumens withinthe catheter body. In such cases, both impellers will usually comprise atubular or solid shaft having a helical rotor formed over the outersurface thereof. Rotation of the shaft thus selectively infuses oraspirates material through the associated catheter lumen. Alternatively,the first and second impellers may comprise a common tubular shaft wherea first helical rotor is mounted over the exterior surface and a secondhelical rotor is mounted over an interior surface of the shaft lumen. Bycounterwinding the two helical rotors, it will be appreciated that theouter rotor will transport material in a first direction while the innerrotor transports the material in opposite direction. Thus, material maybe infused through the annular lumen formed between the outside of thetubular shaft and the catheter body lumen and aspirated back through theinterior of the tubular shaft, or vice versa.

As with the prior embodiments, the circulation catheter may furthercomprise a material capture device disposed at the distal end of thecatheter body, such as a funnel structure, a macerator, or the like.Alternatively, the catheter body may be substantially free fromsurrounding structure.

In a fourth aspect of the present invention, a mechanical pump for usein a medical device comprises an elongate hollow, flexible inner tubehaving a proximal end, a distal end, and a central guidewire lumen. Afirst coiled (helical) rotor element having a distal end and a proximalend is disposed over an outer surface of the inner tube. A jacketsecures the coiled rotor element to the outer surface to complete themechanical pump. The mechanical pump structure may then be used in thelumen of a catheter body or elsewhere in order to provide a pumpingaction in the manner of an Archimedes screw. Preferably, the inner tubehas an outer diameter in the range from 0.5 mm to 5 mm, usually from 1mm to 2 mm. The assembled coiled rotor will have a width in the diameterfrom 0.5 mm to 10 mm, preferably from 0.5 mm to 3 mm, and a pitch overthe inner tube in the range from 1 turns/cm to 50 turns/cm, preferablyfrom 3 turns/cm to 10 turns/cm. Optionally, the mechanical pump mayfurther comprise a second coiled rotor element disposed over an innersurface of the central lumen of the inner tube. The first and secondcoiled rotors will usually be counterwound so that the pump may directflow in both a distal direction and a proximal direction when the innertube is rotated in a single direction. Alternatively, the first andsecond coiled rotors may be co-wound so that the pump may provide anincreased flow through a catheter lumen when the pump is rotated ineither direction. In a particular aspect of the present invention, adistal portion of the coiled rotor may be unattached to the outersurface of the inner tube so that said unattached portion forms orprovides a “whip” element as the pump is rotated. The whip element willbe suitable for mechanically disrupting clot, thrombus, or otherocclusive materials when the pump is rotated in a body lumen.Alternatively, the whip may be used to mix the thrombolytic or otheragents (as set forth above) which are being introduced by the pump in ablood vessel or other body lumen.

The mechanical pump just described may be fabricated by providing ahollow flexible tube, placing a resilient coiled rotor over an outersurface of the tube, and forming a jacket over at least a portion of theouter surface of the tube. In this way, the coiled rotor is secured tothe outer surface of the flexible tube. Such a fabrication method isinexpensive and provides a high quality product. Placing the resilientcoil over an outer surface of the inner tube may comprise winding thecoil over the surface to successively place individual turns of the coilas the inner tube is rotated. Alternatively, a pre-formed coil may bepartially “unwound” to increase its diameter and permit the coil to belocated over the exterior surface of the inner tube. When in the properlocation, the coil may be allowed to rewind over the surface to providean interference fit. The interference fit can be enhanced by heating thewire. Preferably, the coil is then secured to the outer surface of theinner tube by forming or placing a jacket over the structure. Forexample, the jacket formed by dip coating the assembly of the tube androtor(s) into an appropriate curable liquid polymer, such as nylon,polyurethane, polyimide, polyamide, PTFE, FEP, and the like. The coatingcan then be heated and/or radiation cured to induce cross-linking.Further, alternatively, the jacket may be placed by providing a heatshrinkable polymeric tube or sleeve, placing said tube or sleeve overthe combination of inner tube and helical rotor, and then shrinking thejacket over the inner tube and coiled rotor to hold the two together.Further alternatively, the jacket may be formed by extruding a polymericmaterial directly over the inner tube and coil, or by vapor depositionor spray coating. In an alternative embodiment, the coil may be attachedto the inner tube by an adhesive.

The present invention still further comprises methods for transportingmaterials between a target site in a body lumen of a patient in alocation external to the patient. The distal end of the catheter isintroduced to the target site over a guidewire. First impeller isrotated over the guidewire within a lumen in the catheter to transportmaterial between the distal end of the catheter and a proximal end ofthe catheter. The material may be selectively transported in a firstdirection by rotating the impeller for aspiration, and a vacuum may beapplied to the lumen of the catheter to assist in transporting materialfrom the distal end. Alternatively, the impeller may be selectivelyrotated to transport material from the proximal end of the catheterthrough the catheter lumen to the distal end of the catheter, e.g., toinfuse materials. In such instances, the materials may be provided tothe catheter lumen under pressure to assist in transporting the materialthrough the catheter lumen to the distal end of the catheter.

In some instances, the direction in which the impeller is rotated may bechanged. Thus, at one time, the impeller may be rotated in a firstdirection to infuse materials to the target site within a body lumen. Ata subsequent time, the impeller may be rotated in the opposite directionto remove or aspirate materials from the same target site.

In still another instance, a second impeller may be provided in thecatheter and rotated to selectively transport material between theproximal end of the catheter and the distal end of the catheter. Bysimultaneously rotating the first impeller to transport material in anopposite direction, a circulation of material may be established.

In still another instance, first and second impellers may comprisecounterwound helical rotors mounted on a common tubular member. In suchan instance, rotation of the tubular member in one direction will causea first rotor to infuse materials to the target site while the secondrotor aspirates materials from the same target site. In all instances,infusion and aspiration may be assisted by applying pressure or avacuum, as appropriate. The first impeller will conveniently be mountedon the outside of the tubular member, e.g., by any of the methodsdescribed above for placing a coiled rotor over a shaft member. Thesecond impeller will usually be in the form of a helical rotor disposedwithin the lumen of the tubular member. The helical rotor may be “wounddown” to assume a low profile, inserted into the tubular member lumen,and then allowed to unwind to provide an interference fit with the lumenwall. The coil may be further secured or attached to the lumen wall byany of the methods described above.

In still another aspect of the present invention, a method forselectively infusing and aspirating materials between a target site in abody lumen or patient and the location external to the patient,comprises introducing a distal end of the catheter to the target site.An impeller within the lumen of the catheter is rotated in a firstdirection to infuse material to the target site. Sequentially, theimpeller is rotated in a second direction to aspirate material to thetarget site. Such infusion and aspiration can be particularly usefulwith the delivery of thrombolytic agents to blood vessels and theremoval of lysed clot from those blood vessels.

In yet still another aspect of the present invention, a method forcirculating materials through a target site in a body lumen of a patientcomprises introducing a distal end of the catheter to the target site. Afirst impeller within the lumen of the catheter is rotated to transportmaterial to the target site. A second impeller within a lumen of thecatheter is rotated to transport material away from the target site. Thefirst and second impellers may be located within separate lumens withinthe catheter, or alternatively, may be located within the same lumenwithin the catheter. In latter case, first and second impellers willusually comprise a flexible inner tube having a first helical rotorformed over an outer surface thereof and a second helical rotor formedover an inner luminal surface thereof. The first and second helicalrotors are counterwound so that rotation of the inner tube in onedirection will cause flow over the tube in a first direction and flowthrough the tube in the opposite direction.

In particular, the present invention provides an elongate mechanicalpump component that can be used in an aspiration catheter as a standalone device, or as part of the shaft construction of a therapeuticdevice to remove the material fragmented by the working end of thetherapeutic device. The mechanical pump component is hollow, forming aguidewire lumen to allow it to be compatible with use over a guidewire,or with devices requiring a guidewire.

In an exemplary embodiment the pump device is formed from a resilientwire coil, wound along the length of a hollow flexible polymer tube, andbonded or attached thereto by an outer polymer coating that cross linksor heat bonds to the inner tube. The coil member can be of variousgeometric cross sectional shapes. The outer polymer coating ispreferably made of a thinner wall plastic than the inner hollow tube toassist in the attachment process. The thin wall coating also allows thestruts of the coil member to protrude from the surface of the inner tubewhich, when rotated, provide the pumping action.

The present invention may also incorporate an outer sheath surroundingthe mechanical pump to form a catheter device. The catheter device wouldbe attached to a rotating motor drive unit (MDU) at the proximal endallowing the mechanical pump component to rotate at varying speeds,while the catheter sheath remains stationary. Optionally, the MDU canselectively drive the pump element in a clockwise or counterclockwisedirection relative to the longitudinal axis of the device. In use, anymaterial to be removed is evacuated through the annular space betweenthe mechanical pump and the outer sheath and is moved proximally by therotating coils of the mechanical pump.

In another aspect of the invention, a circulation catheter having aclearing element is disclosed. The catheter generally comprises: acatheter body having a proximal end, a distal end, and a lumentherebetween, the lumen forming a distal opening at the distal end ofthe catheter body; an impeller rotatably disposed in the lumen of thecatheter body to aspirate materials from the distal end to the proximalend of the catheter body; and a clearing element disposed at the distalopening of the catheter body to prevent the materials from accumulatingat the distal opening. In general, the clearing element spins relativeto the catheter body to clear the distal opening of the catheter body asthe shaft is rotated.

The circulation catheter may further comprise a material capture device,such as a macerator disposed at the distal end of the catheter body. Insome embodiments, the macerator comprises a distal end and a proximalend, wherein the proximal end of the macerator extends into the distalopening of the catheter body to form the clearing element.

In another embodiment, the clearing element comprises a cutting membercoupled to the impeller at or near the distal opening. The cuttingmember may be attached to the proximal end of the macerator.Alternatively, the cutting member is attached to a shaft coupled to theimpeller.

In one aspect of the invention, a method for transporting materialsbetween a target site in a body lumen, and a location external to thepatient comprise: introducing a distal end of a catheter to the targetsite; rotating an impeller within a lumen of the catheter to aspiratematerial from the target site; and clearing an opening of the lumen atthe distal end of the catheter body to prevent the material fromaccumulating at the opening.

Generally, clearing the opening comprises rotating a clearing elementinside the distal opening of the catheter body. In some embodiments, theimpeller has shaft and a helical rotor, wherein rotating the impellerfurther comprises rotating a macerator attached at a distal end of theimpeller shaft, and wherein clearing the opening of the lumen comprisesspinning a proximal end of the macerator inside the distal opening ofthe catheter body.

In another embodiment the clearing element is coupled to the impeller,and the clearing element is spun inside the distal opening of catheterbody as the impeller is rotated to clear the opening of the lumen. Theclearing element may comprises a cutting disk that is attached to theshaft or rotor of the impeller or the proximal end of the macerator.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a first embodiment of material transport catheterconstructed in accordance with the principles of the present invention.

FIG. 1A is a detailed view of the proximal end of the catheter of FIG.1, shown in partial cross-section.

FIG. 1B is a detailed view of the distal end of the catheter of FIG. 1,shown in cross-section.

FIG. 1C is an alternative distal end of the catheter of FIG. 1, shown incross-section.

FIG. 1D illustrates a second embodiment of a material transport catheterconstructed in accordance with the principles of the present invention.

FIG. 1E is a cross-sectional view taken along the line 1E-1E on FIG. 1D.

FIG. 2 illustrates use of the material transport catheter of FIG. 1 inperforming an infusion/aspiration procedure according to the methods ofthe present invention over a guidewire.

FIGS. 3A-3D illustrate the components of a mechanical pump constructedin accordance with the principles of the present invention.

FIGS. 4A and 4B illustrate cross-sectional views of alternativeconstructions of the mechanical pump of FIGS. 3A-3C.

FIG. 5 is a perspective view of a clot disruption catheter systemconstructed in accordance with the principles of the present inventionand employing a mechanical pump as part of a material transportmechanism.

FIG. 5A is a detailed view of the distal end of the clot disruptioncatheter system of FIG. 5, with portions broken away.

FIG. 5B is a detailed view of a portion of the proximal end of the clotdisruption catheter of FIG. 5, with portions broken away.

FIGS. 6, 6A, and 6B illustrate a second exemplary clot disruptioncatheter constructed in accordance with the principles of the presentinvention and employing a material transport mechanism.

FIGS. 7A and 7B illustrate the distal portion of a third embodiment of aclot disruption catheter constructed in accordance with the principlesof the present invention and employing a material transport mechanism.

FIG. 8 illustrates use of the catheters of FIG. 5 and FIGS. 7A and 7B incombination.

FIG. 9 illustrates a kit constructed in accordance with the principlesof the present invention.

FIG. 10 illustrates a circulation catheter employing a clearing elementin accordance with the present invention.

FIG. 11 illustrates an alternative circulation catheter having a cuttingdisk as a clearing element.

DESCRIPTION OF THE SPECIFIC EMBODIMENTS

An exemplary material transport catheter in the form of a mechanicalaspiration device constructed in accordance with the present inventionis illustrated in FIG. 1. The aspirating device 10 comprises a catheterbody 12, having an adapter “Y” hub 14 at a proximal end thereof, anaspiration/injection tube 13 on the hub 14, an impeller 16 having ahelical rotor to define a “coiled pump member” operatively coupled to amotor drive unit (not shown) by drive shaft and spindle assembly 19.Optionally, the device may include a hemostasis sheath (not shown)either as part of the catheter sleeve, or as a separate device throughwhich the aspirating device is inserted. Depending on the desiredclinical result, the impeller 16 can be recessed within the catheterouter sheath 12, flush with the end of the catheter outer sheath, orextend distally of the catheter outer sheath, by varying the length ofthe coiled pump member, the catheter outer sheath, or both.

As shown in FIG. 1A, the catheter body 12 has a port 15 which is alignedwith the aspiration/injection tube 13 so that materials may be removedfrom the lumen 17 of the catheter body 12 and/or infused into the lumen.The coiled pump member continues from the distal end of the catheterbody 12 (as shown in FIG. 1) all the way into the proximal hub 14 sothat material may be transported to or from the distal end depending onthe direction of rotation of the coiled pump member 16.

FIG. 1B is a cross-sectional view of the distal end of the catheter body12, showing the entry of coiled pump member 16 into the lumen 17.Alternatively, the coiled pump member 16 could terminate at (or before)the distal end of the catheter body 12, as shown in FIG. 1C. In such anembodiment, infusion/aspiration ports could be provided along the distalend of the catheter body 12 (not illustrated).

Referring now to FIGS. 1D and 1E, a second embodiment of a materialtransport catheter constructed in accordance with the principles of thepresent invention will be described. Material transport catheter 40comprises a catheter body 42 which may be adapted for introduction tothe vasculature or other body lumens of a patient. The catheter body 42includes a first impeller 44 and a second impeller 46, where eachimpeller comprises a solid central shaft and helical rotor 45 and 47,respectively, formed over the shaft. The catheter body 42 has a distalend 48 and a proximal hub 50. The proximal hub 50 includes an aspirationport 52 connected to a lumen 60 (FIG. 1E) in which the first impeller 44is disposed. The hub 50 has a second infusion port 54 which is connectedto lumen 62 (FIG. 1E) in which the second impeller 46 is disposed. Theimpellers 44 and 46 have drive connectors 56 and 58 at their proximalends. The drive connectors may be connected to suitable drive unit(s)for rotation of the impellers in a desired direction. The catheter bodyalso includes a separate guidewire lumen 64 to permit introduction ofthe material transport catheter 40 over a guidewire in a conventionalmanner. The catheter 40 may used by infusing a material through port 54,usually under pressure, with the assistance of the second impeller 46.That is, the second impeller will be rotated in the direction whichcauses the rotor 47 to advance material through the lumen 62 in a distaldirection. Similarly, a material may be aspirated through the lumen 60by rotating rotor 44 in a direction which transports the materialsproximally through the lumen. Aspiration is optionally assisted byapplying a vacuum to the port 52. The infusion and aspiration may beperformed sequentially, simultaneously, or both at various points duringa particular procedure. In particular, the catheter 40 may be used tocirculate a thrombolytic or other therapeutic material to a target siteand thereafter withdraw lysed or other treated materials from thattarget site without the need to remove or exchange the catheter.

In operation, as depicted in FIG. 2, the aspirating catheter 10 ispercutaneously inserted through an introducer sheath 21, and into thelumen of the vessel or synthetic graft from which material is to beremoved. In the example shown, the aspirating catheter 10 is insertedinto an arterio-venous dialysis graft G, and tracked over a guidewire 22to the area containing thrombus or obstructive matter OB. A motor driveunit 18 is then activated to rotate the impeller 16. At the point theaspirating catheter comes into contact with the material to be removed,the material is pulled into the lumen of the catheter body and funneledor pumped proximally by the rotor as it rotates within the catheterlumen.

Detailed construction of an exemplary impeller 30 is shown in FIGS. 3Aand 3B. Inner tube 32 is formed of a flexible polymer material,preferably a polyimide, but can also be made from any thermoplastic, forexample polyethylene or nylon or a thermoset, for example urethane. Insome cases, it would be possible to form the inner tube from a flexiblemetal, such as a shape memory alloy, as Nitinol® alloy. The inner tube32 is either extruded as a hollow tube, or formed around a mandrel (notshown), to create a central guidewire lumen 35 (FIG. 3B). Optionally, inorder to enhance the torqueability of the shaft, it may be desirable toform the inner tube as a braid coil, stacked coil, or coil-reinforcedextrusion. Suitable coils for forming the inner tube may be constructedas multi-filar coils, counterwound filament coils, or stacked filamentcoils. The filaments forming the coils may be composed of metals orpolymers. In the preferred embodiment, inner tube 32 has an outerdiameter in the range of 0.02 inch (0.5 mm) to 0.06 inch (1.5 mm),preferably 0.04 inch (1 mm), and an inner (central lumen) diameter inthe range of 0.015 inch (0.38 mm) to 0.045 inch (1.1 mm) to accommodatevarious common sizes of guidewires through the central lumen, preferablyand an inner diameter of 0.021 inch (0.533 mm) to accommodate a 0.018inch (0.46 mm) guidewire. A resilient coil 34 is wrapped over the outersurface of the inner tube 32 to a desired length, preferably over atleast a major portion of the length of the inner tube, usually over atleast 50% of the inner tube length, more usually at lest 75%, and mostoften at least 90% or more, and often running coextensive therewith.

Resilient coil 34 may be a single filament structure, a multiplefilament structure, a plurality of filaments, a multi-filar structure,or the filaments may be a round wire, a ribbon wire, or a wire having anirregular cross-section, further where the filaments may have the samediameter, different diameters, and/or may be stacked. The coils willusually be a metal, but could also be formed from a variety of polymers.The exemplary coil 34 is formed of a round wire, preferably an 0.014inch (0.36 mm) diameter 304 stainless steel wire, but can also be formedfrom Nitinol® alloy (NiTi), Elgiloy® or Titanium. Alternatively, itcould be formed from a high durometer polymer or polymer fiber with ahigher melt temperature than inner tube 32, such as PEEK or Kevlar®. Inan alternative embodiment, coil 34 may have a geometric cross sectionalshape other than round, such as oblong, triangular, or square.

The pitch of the resilient coil 34 can also be defined in terms of thedistance between successive turns of the coil or still furtheralternatively, as the “turns/cm.” A table setting forth all thepertinent dimensions of the exemplary impeller 31, including thealternative pitch dimensions, is set forth below.

TABLE I EXEMPLARY DIMENSIONS Inner Tube 32 Broad Narrow Outer DiameterD_(M) 0.5 mm to 5 mm   1 mm to 2 mm Inner Diameter D_(i) 0.4 mm to 2.9mm 0.5 mm to 1.9 mm Length  5 cm to 250 cm  45 cm to 125 cm Coil 34Diameter D_(W) 0.02 mm to 2.5 mm  0.15 mm to 0.5 mm  Pitch P 0.2 mm to10 mm  1 mm to 4 mm (turns/cm)  1 to 50  3 to 10 Coil Assembly Width 0.5mm to 10 mm  0.5 mm to 3 mm   C_(W)

As illustrated in FIG. 3C, an outer jacket 36 is formed over the innertube 32 and rotor 34 of the impeller 30, usually by dip coating the tube32. The coated assembly is then subjected to heat bonding orcross-linking to adhere the outer coating 36 with the inner tube 32,thereby encapsulating coil member 34. The jacket coating is preferablymade of the same material as is chosen for the inner tube 32 or othermaterial capable of heat bonding or cross-linking therewith, such asnylon, polyamide, polyurethane, PTFE, FEP, and the like. Jackets formedby dip coating will have a much thinner wall thickness than inner tubemeasuring in the range of 0.001 inch to 0.002 inch. While the inner tube32 has been illustrated as being a solid polymeric tube, in someinstances it will be possible to utilize a coil as the inner tube.Placement of a jacket coating over the coil member 34 which forms theimpeller and an inner member formed as a coil would help strengthen theinner coil member while still leaving it quite flexible.

Alternatively, the outer jacket 36 may be formed by other conventionaltechniques, such as heat shrinking a polymeric sheath or tube over theassembly of the inner tube 32 and coil 34, where the sheath material maybe the same as or different than the underlying tube 32. Heat shrinkingof a jacket would be particularly effective if the tube 32 is formedfrom a non-polymer, such as a shape memory metal alloy. In some cases,it might also be possible to extrude or spray the outer jacket 36 overthe assembly of the inner tube 32 and rotor 34.

An impeller 400 (FIG. 3D) comprising a tubular member 402 has a helicalchannel 404 formed in its outer surface 406. The helical channel 404 maybe formed by embedding a wire, ribbon, cable, small diameter tube, orother element that can be wrapped into a helical shape into the outersurface 404. When the embedded element is removed, the channel or groove404 will be left in place. The resulting helical channel or groove 404will act as the impeller surface as the impeller 400 is rotated asdescribed elsewhere in this application. Thus, the combination of thehelical groove 404 and remaining surface 406 of the impeller 400 willconstitute the helical rotor described elsewhere herein in both thespecification and claims.

Referring now to FIGS. 4A and 4B, impellers capable of bi-directionaland enhanced material transport are illustrated. In FIG. 4A, abi-directional impeller 60 comprises an inner tube 62 having theproperties generally described above in connection with impeller 30. Afirst helical rotor 64 is formed over the outer surface of inner tube32, again generally as described above for impeller 30. Bi-directionalimpeller 60 differs, however, in that it includes a second helical rotor66 disposed in a central lumen 68 of the inner tube 62. The rotor 66 maygenerally have the same characteristics as described above for rotor 64,but will have a generally smaller diameter (so that it fits within thelumen) and will be wound in a direction opposite to that of the firstrotor 64. Thus, the helical rotors 64 and 66 will be “counterwound” withrespect to each other. By providing rotors which are counterwound, itwill be appreciated that rotation of the impeller 60 within a lumen of acatheter body (not illustrated in FIG. 4A), will induce materialtransport in opposite directions. Material transport in a firstdirection may be achieved in the annular region between the outersurface of inner tube 62 and the inner surface of the luminal wall ofthe catheter body. In contrast, material transport flow through thecentral lumen 68 of the inner tube 62 will be in a direction opposite tothat of flow in the annular space since the rotors 64 and 66 are woundin opposite directions. That is, if the helical rotor 64 has aright-handed coil direction, the second rotor 66 will have a left-handedcoil direction.

Referring now to FIG. 4B, the use of first and second helical rotors onan impeller may also be used to provide enhanced or modified materialtransport flow in a single direction. Impeller 70 includes an inner tube72, a first helical rotor 74, and a second helical rotor 76.Construction of the impeller 70 may be very similar to that of impeller60, except that the first helical rotor 74 and second helical rotor 76will be wound in the same direction. The pitches and specific dimensionsof the helical rotors may vary from each other, and may vary along theirlengths, but they will both be configured to deliver material through acatheter lumen in the same direction when the impeller is rotated ineither direction. Such a design has many potential advantages. First, itcan provide for higher volumetric and mass flows then is achievable whenthe second rotor 76 is absent. It can provide for different flow ratesto different portions of the catheter. It can permit two differentstreams of the same or different materials to be delivered to a singleor multiple locations within the catheter. It could also be useful toprovide a mixing catheter where two different fluids are delivered andthe mixed in situ at the distal end of the catheter. The latter isparticularly advantageous for chemicals and reagents that cannot bepremixed prior to delivery.

Impeller 60 has other advantages. By providing for bidirectional flowusing a single impeller, circulation and recirculation of materials to atarget site within a patient body lumen may be achieved. For example, athrombolytic agent could be introduced through the central lumen 68 ofthe impeller 60 while lysed clot, thrombus, or other occlusive materialsare aspirated from the same target location in the annular lumen formedover the impeller. Other uses and advantages of the system will also befound.

Referring now to FIG. 5, a clot disruption system 110 constructed inaccordance with the principles of the present invention will bedescribed. The clot disruption system 110 includes a clot disruptioncatheter 112 and a motor drive unit 114. The catheter 112 has a distalsection 116 which comprises an expansible cage and macerator componentsof the catheter, as described in greater detail in connection with FIGS.5A and 5B. A proximal hub 118 is secured to the proximal end of thecatheter 112 and removably connectable to the motor drive unit 114. Themotor drive unit 114 will be configured to transmit rotational and/oraxial translational forces through a tubular shaft 122 (FIGS. 5A and 5B)to manipulate the macerator. A slidable ring 124 is shown schematicallyon the motor drive unit 114 and is intended, for example, to permitaxial translation of the macerator. Such axial translation, however, isnot essential and is only an optional feature of the present invention.

The distal section 116 of the clot disruption catheter 112 is bestillustrated in FIG. 5A. The distal section 116 comprises a radiallyexpansible cage 126 which may have any of the forms and structuresdescribed above. In particular, cage 126 may comprise a plurality ofhelical wires or other elements. Alternatively, the cage may comprise aplurality of straight, axially aligned wires or other elements. Theexpansible cage 126 will be self-expanding, i.e., it will assume itsradially expanded configuration absent any constraining forces, althoughit could utilize active means for expansion in other embodiments. Thecage 126 is shown in its expanded configuration in FIGS. 1 and 5A. Thedistal tips of the cage elements are attached to a nose cone 128 whichmay be fixed or floating relative to the main portion of the catheterbody 112, as described in more detail below.

The body of clot disruption catheter 112 will have a lumen 130 extendingfrom hub 118 to the distal section 116, and the tubular shaft 122 willbe disposed within the lumen 130. A distal end 132 of the tubular shaft122 will be connected to the nose cone 128, and the shaft willpreferably have an inner lumen 134 which terminates in a series ofinfusion ports 136 (which may be circular, as illustrated or may beelongate slits or may have a variety of other geometries) disposedbetween the distal end of the body of catheter 112 and the nose cone128. The lumen 134 and infusion ports 136 will be useful, for example,for delivering thrombolytic and other agents used in connection withclot disruption. The lumen will also be able to receive a guidewire 120(not shown) which exits through distal port 135 to facilitatepositioning within a blood vessel or other body lumen.

Macerator 140 is disposed on the tubular shaft 122 within the expansiblecage 126. The macerator 140 is illustrated as a helical wire orfilament, but could comprise a variety of other structures. Helical wire142 is formed from spring material, typically a spring stainless steelor shape memory alloy, and is fixedly attached to the shaft 122 at bothends. First attachment point 144 is visible in FIG. 5A, while the secondattachment point is hidden behind the shaft. With this configuration ofwire 142, it will be appreciated that the macerator 140 isself-expanding. Radial compression forces will cause the element 142 tocollapse radially inwardly against the exterior of shaft 122.

Macerator 140 comprising helical wire 142 is intended to operate byrotation of the shaft 122. When the shaft 122 is rotating, the helixwill trace a generally ovoid shell within the expansible cage 126, thusengaging and disrupting occlusive material which is within the cage.Optionally, although not necessarily, the macerator 140 may beconfigured to engage at least a portion of an inner surface of theexpansible cage 126. In particular, when treating clot within bloodvessels, the helical wire 142 will disrupt the clot and engage andentangle materials within the clot, particularly fibrin fibers whichmake up a substantial portion of the clot material. By breaking up andengaging the clot in this fashion, the clot is pulled away from theblood vessel wall rather than sheared from the wall as in many priorthrombectomy and atherectomy procedures. In particular, the combinationof the expansible positioning cage 126 and the macerator which is spacedradially inward from the shell defined by the cage, clot removal anddisruption can be performed with minimum risk of injury to the bloodvessel wall.

The expansible cage 126 and macerator 140 will usually be radiallycollapsed to facilitate introduction and withdrawal of the catheter 112to and from a target site within the vasculature or other body lumen.The necessary radial constraint can be provided in a number of ways. Forexample, a tether or filament could be wrapped around both the cage 126and the macerator 140, with the constraint being removed when the devicereaches the target site. Alternatively, the cage 126 and/or themacerator 140 could be composed of a heat memory material, permittingdeployment by use of an induced temperature change, e.g., by passing anelectrical current through the structures or by infusing a heated orcooled fluid past the structures. Preferably, however, a radialconstraint will be provided by a sheath 146 which can be axiallyadvanced to radially collapse both the cage 126 and macerator 140.

The catheter 112 further comprises a mechanical pump to assist in theremoval of disrupted clot and other debris which is produced byoperation of the macerator. The mechanical pump may comprise a helicalrotor 148 which is disposed over the outer surface of the tubular shaft122, as illustrated in both FIGS. 5A and 5B. Preferably, although notnecessarily, the helical rotor 148 will extend from the proximal side ofthe macerator (helical wire 142) all the way into the interior of thehub 118. In this way, disrupted clot on other fluid materials can bepumped proximally by the rotor 148 (which acts as an “Archimedes screw”)as the macerator and tubular shaft are rotated.

Referring now to FIG. 5B, the construction of proximal hub 118 will bedescribed. A rotating hemostatic fitting 150 is provided at the proximalend of catheter 112 and mates with the distal end of hub body 152.Tubular shaft 122 passes from the lumen 130 of catheter 112 into theinterior 154 of hub body 152. A rotating hemostatic seal structure 156is also provided within the interior 154 and divides the interior into afirst isolated region 158 and a second isolated region 160. The firstisolated region 158 has connector branch 162 which permits aspiration offluids and materials through the lumen 130 of catheter 112. A secondconnector branch 164 opens to the second isolated region 160 and permitsinfusion of therapeutic agents, such as thrombolytic agents, into thelumen 134 of the tubular shaft 122 through ports 168. A rotating seal170 is provided at the proximal end of the hub and a hemostatic valve172 is provided on the proximal end of tubular shaft 122 to permitintroduction of a guidewire. The connector 172 will also be suitable forcoupling to the motor drive unit 114 (FIG. 5) to permit rotation ofshaft 122 which in turn rotates the macerator 140. Note that the hub 118illustrated in FIG. 5B is not suitable for axial translation of theshaft 122 relative to the catheter 112.

Referring now to FIGS. 6, 6A and 6B, a second exemplary clot disruptioncatheter 200 will be described. The catheter 200 includes a catheterbody 202 and a tubular shaft 204 which is rotatably and axially slidablyreceived in a lumen of the catheter body. The catheter 200 has a distalsection 206 including a radially expansible cage 208 and a macerator 210in the form of an arcuate wire. In contrast to catheter 112 of the firstembodiment, both the expansible cage 208 and macerator 210 will beselectively and controllably expansible in the clot disruption catheter200.

Referring in particular to FIGS. 6A and 6B, the tubular shaft 204extends through lumen 203 of the catheter body 202 and terminates in anose cone 212. A bearing structure 214 receives the tubular shaft 204and permits both rotation and axial translation thereof relative to thecatheter body 202. While the bearing 214 could be positioned directly onthe distal tip of the catheter body 202, that would block lumen 203 andprevent collection of disrupted clot or other occlusive materialtherein. Thus, it is desirable to mount the bearing structure 214 distalto the distal end of catheter body 202, e.g., on spacer rods 216, toprovide an opening or gap which permits aspiration of disrupted clot orother material through the lumen 203. The distal end of tubular shaft204 is mounted in a second bearing structure 218 located in the nosecone 112. Bearing structure 218 permits rotation but not axialtranslation of the shaft 204. Thus, when the shaft 204 is drawnproximally in the direction of arrow 220 (FIG. 6B), the distance betweenthe nose cone 212 and the bearing structure 214 is reduced. This causesthe elements of cage 208 to axially shorten and radially expand. Whilethe elements of cage 208 are shown as axial wires or filaments, it willbe appreciated that they could be helical or have any one of a varietyof other configuration which would permit radial expansion upon axialcontraction. Similarly, the macerator wire 210 is fixedly attached tothe tubular shaft 204 at an attachment point 222. The other end of themacerator wire 210 is connected at attachment point 224 to the portionof bearing structure 214 which rotates together with the tubular shaft204. In this way, the macerator is both axially shortened so that itradially expands and is able to rotate when the tubular shaft 204 isrotated, e.g., in the direction of arrow 226.

The clot disruption catheter 200, the clot includes a mechanical pumpcomponent to assist in extraction of clot or other disrupted materialsthrough the lumen of the catheter. As best seen in FIGS. 6A and 6B, themechanical pump comprises a simple helical screw, such as a helicallywound wire or other element 230. Such a helical screw pump is commonlyreferred to as an “Archimedes” screw pump and operates by creating avertical flow as the screw pump is rotated. While in some instances useof the screw pump may be sufficient in itself to remove materials, thescrew pump will most often be used in combination with vacuum aspirationto remove materials through the lumen of the catheters.

An additional exemplary clot disruption catheter 300 is illustrated inFIGS. 7A and 7B. The clot disruption catheter 300 comprises catheterbody 302 having an expansible cage 304 at its distal end. In contrast toprevious embodiments, the expansible cage 304 is in the form of aconical “funnel” which may be formed from impervious materials (whichwill not permit the bypass of blood or other luminal flows) or from“filtering” materials which will permit blood or other bypass flows.Preferably, the funnel will be formed from pervious materials, such aswire meshes, perforate membranes, woven fabrics, non-woven fabrics,fibers, braids, and may be composed of polymers, metals, ceramics, orcomposites thereof. The filters will have a pore size selected to permitblood flow (including blood proteins) but capture disrupted clot andother embolic debris. Useful pore sizes will be in the range from 20 μmto 3 μm.

The funnel will usually be formed from a flexible filter material andsupported on a plurality of rods 306 which can be actively or passivelydeflected in order to open or close the conical cage. Most simply, therod members 306 will be resilient and have a shape memory which opensthe cage structure in the absence of radial constraint. Thus, catheter300 may be conveniently delivered through a sheath, in a manneranalogous to that described in connection with FIG. 5. The clotdisruption catheter 310 further includes a macerator assembly 310, bestobserved in FIG. 7B. The macerator comprises a tubular shaft 312, suchas a highly flexible coil shaft adapted to transmit rotational torque.Tubular shaft 312 will include an internal lumen to permit introductionover a guidewire 314. A helical macerator wire 316 has a distal end 318attached to the distal end of shaft 312. A proximal portion 320 of themacerator 316 extends through a tube 322 attached to the side of thetubular member 312. In this way, the helical portion of macerator 316,which has a helical memory shape, can be expanded and contracted byaxially translating the proximal portion 320. Although illustratedpassing through a separate tubular member 22, the proximal portion 320could pass through the same lumen of the tubular shaft 316 as does theguidewire 314. It will be appreciated that the macerator structure 316could be employed with any of the previous embodiments where it isdesired to provide for selective expansion and contraction of themacerator.

The proximal portion 320 of the macerator 316 will comprise a helicalrotor 322 to form an impeller as described in connection with previousembodiments of the material transport catheters of the presentinvention. The impeller will act to assist in the aspiration ofmaterials macerated by the macerator 310 and collected in the funnel304, typically in combination with application of a vacuum at theproximal end of the catheter 300 (not shown).

Referring now to FIG. 8, use of clot disruption catheter 200 and clotdisruption catheter 300 for performing a procedure in accordance withthe principles of the present invention will be described. The catheters200 and 300 are introduced to a region within the patient's venoussystem, e.g., at the junction between the iliac veins IV and theinferior vena cava IVC. Blood flow is in the direction from bottom totop, and catheter 200 is introduced into the iliac vein IV in anantegrade direction, i.e., in the direction of blood flow. Catheter 300is introduced into the inferior vena cava IVC in a retrograde direction,i.e., against the flow of blood. Filtering cage 304 is expanded so thatthe distal end of the “funnel” engages and generally seals around theinterior wall of the inferior vena cava. Positioning cage 126 oncatheter 200 is advanced into a region of clot C within the iliac veinIV and the macerator (not shown) is activated in order to disrupt theclot. Mechanical pumping and optionally aspiration will be appliedthrough port 162 in order to draw a portion of the disrupted clot out ofthe patient's vasculature. Further optionally, a thrombolytic agent maybe introduced through port 164. Pieces of the disrupted clot DC,however, may be released into the blood flow so that they pass from theiliac vein IV into the inferior vena cava. By positioning thefunnel-like cage 304 of catheter 300 within the inferior vena cava,however, the disrupted clot may be captured and, optionally, furtherdisrupted using the macerator assembly within catheter 300. Thismaterial may then be aspirated through port 162, being transported usinga mechanical pump as elsewhere described herein.

Turning now to FIG. 9, the present invention further comprises kitswhich include at least a catheter, which is shown to be catheter 200 butcan be any other mechanical transport catheter in accordance with themethods of the present invention. The kit will further includeinstructions for use IFU setting forth any of the methods describedabove. Optionally, the kit may further comprise a motor drive unit 114(particularly a dual direction drive unit) or other kit components, suchas a guidewire, a thrombolytic agent, or the like. Usually, the kitcomponents will be packaged together in a pouch P or other conventionalmedical device packaging, such as a box, tray, tube, or the like.Usually, at least the catheter component will be sterilized andmaintained sterilely within the package. Optionally, the motor driveunit may not be included with the kits, but may instead be provided as areusable system component. In that case, usually, the catheter will bedisposable.

Now referring to FIG. 10, the present invention comprises a circulationcatheter 400 having a clearing element 410. The catheter generallycomprises a catheter body 412 having a lumen forming a distal opening414 at the distal end of the catheter body. The circulation catheteralso has an impeller 416 rotatably disposed in the lumen of the catheterbody to aspirate materials from the distal end to the proximal end ofthe catheter body. The impeller 416 may comprise a coiled rotor 422coupled to a shaft 424. The clearing element 410 is disposed at thedistal opening 414 of the catheter body 412 to prevent the materialsfrom accumulating at the opening and restricting flow.

The circulation catheter may further comprise a material capture device,such as a macerator 418 disposed at the distal end of the catheter body412. The distal end of the macerator 418 is fixed to the shaft 424 atthe catheter tip 420. The proximal end of the macerator 418 may extendunattached into the distal opening 414 of the catheter body to form theclearing element 410. In general, the clearing element 410 spinsrelative to the catheter body 412 to clear the distal opening 414 of thecatheter body as the shaft 424 is rotated. The catheter 400 may alsohave an expansible cage 26 surrounding the macerator 418, wherein themacerator 418 engages the expansible cage as it is rotated.

Now referring to FIG. 11, an alternative circulation catheter 450 has aclearing element comprising a cutting member 460 at or near the distalopening. The cutting member 460 may comprise any shape to facilitateclearing of the opening 414 when rotated about the catheter body 412,but generally comprises a thin, hollowed out disk with flanges 462 thatare disposed to break up material as the cutting member is rotated. Thecutting member 460 may be attached to the proximal end of the macerator418. Alternatively, the cutting member may be attached to the shaft 424or impeller 416.

While the above is a complete description of the preferred embodimentsof the invention, various alternatives, modifications, and equivalentsmay be used. Therefore, the above description should not be taken aslimiting the scope of the invention which is defined by the appendedclaims.

1. A circulation catheter comprising: a catheter body having a proximalend, a distal end, and a lumen therebetween, the lumen forming a distalopening at the distal end of the catheter body; a macerator at thedistal end of the catheter body, wherein the macerator isself-expandable; an expansible cage surrounding the macerator; animpeller rotatably disposed in the lumen of the catheter body toaspirate materials generated by the macerator from the distal end to theproximal end of the catheter body; and a clearing element disposed atthe distal opening of the catheter body between the macerator and theimpeller to prevent the materials from accumulating at the distalopening.
 2. A circulation catheter as in claim 1 wherein the maceratoris configured to engage at least a portion of the expansible cage.
 3. Acirculation catheter as in claim 1, the impeller comprising a helicalrotor having a distal end and a proximal end extending at leastpartially over an outer surface of a shaft, wherein a distal portion ofthe shaft extends beyond the distal opening of the catheter body.
 4. Acirculation catheter as in claim 3, wherein the macerator comprises adistal end and a proximal end, and wherein the distal end of themacerator is fixed to the distal end of the shaft, and wherein theproximal end of the macerator extends into the distal opening of thecatheter body to form the clearing element.
 5. A circulation catheter asin claim 3, wherein the rotor comprises a helical coil, and wherein thedistal end of the helical coil is unattached to the shaft to form theclearing element.
 6. A circulation catheter as in claim 3, wherein theclearing element comprises a cutting member coupled to the impeller ator near the distal opening.
 7. A circulation catheter as in claim 6,wherein the cutting member is attached to the macerator.
 8. Acirculation catheter as in claim 6, wherein the cutting member isattached to the shaft.
 9. A circulation catheter as in claim 6, whereinthe cutting member is attached to the helical rotor.
 10. A circulationcatheter as in any of claims 4-6, wherein the shaft is rotated to induceaspiration through the catheter body lumen, and wherein the clearingelement spins relative to the catheter body to clear the distal openingof the catheter body as the shaft is rotated.
 11. A circulation catheteras in claim 1, wherein the macerator expands and collapses in responseto expansion of the cage.